It is commonplace to control oil leakage past a piston in the cylinder of an engine by oil control rings in a groove of the piston. Usually two rings in the groove are biased against the cylinder wall by an expansion ring in the groove. The rings have the function of scraping the oil from the cylinder walls as the piston moves down. To assure the removal of sufficient oil, a high tension is maintained on the rings; this is at the expense of high friction of the rings against the cylinder walls and consequent lowering of engine efficiency. The rings each have ends defining a gap which permits oil leakage and thus limits attempts to lower the oil consumption rate. The rings typically are tensioned by a common expander and are spaced by the expander so that a leakage path exists even though the gaps are not aligned. Further, attempts to improve oil consumption can be limited by the flow of oil under the rings into the groove and out of the groove over the upper ring surface.